This research is intended to show in a unified manner using a previously developed animal model, various phenomena controlling augmentation of healing in an osteotomy when electric currents are applied. Parameters of the electrodes such as electrode current density, total potential, electrode material, periodicity of stimulation, and frequency of stimulation will be studied. The study of these various parameters in the rabbit calvarium model will allow characterization of these variables in a comparable manner. Analysis of the results will be by histologic studies, X-ray evaluation, and mechanical testing. The electrochemical phenomena in and surrounding the electrodes will be studied in an in vitro situation utilizing current densities and waveforms identical to those being utilized in the in vivo experiments. These experiments will be especially crucial when studying the effects of "capacitor" electrodes in which the electrochemical effects at the electrode surfaces are minimized. The biochemical consequence of applying electric currents to bone will be studied by investigating H3 proline uptake, Ca45 uptake, cyclic AMP, and total hydroxyproline. Mathematical models of an electrode in bone will be further developed to better understand the results obtained from the biologic model. These models will be helpful in assessing the spread of currents and calculating current densities between electrodes. The acceleration of ingrowth into porous ceramics and porous metallics will be ascertained. In addition, the facilitated biodegradation rate of tricalcium phosphate materials which has already been preliminarily investigated in this laboratory will be further ascertained. Potentially, this technique will facilitate ingrowth and utilization of prostheses in patients. Porous prosthetic devices might possibly replace the presently utilized methylmethacrylate fixation methods. The present disadvantage of porous devices is their inability to provide rapid stabilization for early utilization by the patient.